DESCRIPTION: Poor children are subjected to detrimental influences in their lives. Some of these negative factors are biological and environmental, such as poor nutrition and exposure to diseases and toxicants. Given that risk factors are unlikely to occur in isolation for disadvantaged children, potential synergistic effects or modifying influences of one risk factor on another should be considered. Furthermore, attempts to reverse negative outcomes are also likely to be influenced by such interactions. The general goal of this study is to examine the interaction between elevated lead and low iron levels on the response to clinical intervention in young children between 18 and 30 months of age. The working hypotheses, based on preliminary findings, are: 1) iron deficiency interferes with excretion of lead and the lowering of blood lead levels; 2) elevated lead levels interfere with correction of iron deficiency; 3) reduction of blood lead is related to young children's cognitive development, particularly for children who have adequate iron stores; 4) correction of iron deficiency, especially increases in hemoglobin, is also related to cognitive outcome; and 5) the combination of iron deficiency and elevated lead levels makes children doubly vulnerable for continued cognitive as well as biochemical abnormalities. To test these hypotheses, the investigators will intervene clinically with disadvantaged children whose blood lead levels range from 10 to 44 ug/dL, with equal numbers of children who are deficient and sufficient in iron. Interventions will include: 1) home inspections and procedures to reduce exposure to lead from paint and dust; 2) iron supplementation. Biochemical outcomes will include blood lead and indices of iron status. Cognitive and behavioral outcomes will include a global measure of cognitive functioning and specific tests of attention, reaction time, and motor activity appropriate for this age range. These will be assessed prior to intervention, six months later and one year later. This study is complementary to an ongoing NIEHS sponsored investigation of chelation therapy and cognitive outcomes in moderately lead poisoned children. In contrast to this multicenter chelation study, children will be studied with a wider initial range of blood lead levels who will not be chelated, but who will receive iron treatment. Therefore, results should be more generalizable to the majority of lead poisoned children.